The invention relates in general to munitions and in particular to firing and data link interconnections for cannon-fired munitions.
Internally-controlled or “smart” munitions have been used for over twenty-five years. Smart munitions launched by cannons have been in development for about five years. Cannon-launched smart munitions may be, for example, 105 mm cartridge case rounds, 120 mm metal stub base/consumable case rounds, or other rounds fitted with contact rings on their breechblock contacting surfaces. In cannons, the traditional firing circuit and breechblock geometry to support the rear quarter access of the firing circuit is over fifty years old.
Cannon-launched rounds may be electrically fired. That is, an electrical contact on the breechblock of the cannon makes contact with the firing plug on the primer of the round. An electrical current is applied to the primer, creating a spark to ignite the black powder, which ignites the propellant located in the round. A data link, for example, a Universal Munition Data Link (UMDL), can support bi-directional communication and transmission of power to some cannon-launched rounds using a set of two pins. Known cannons that launch smart munitions may use UMDL pins and circuits that are packaged separately and independent of the legacy firing circuit. Legacy firing circuits require breechblocks with relatively complex machined geometry. This geometry may include deeply drilled, tight tolerance (<0.002 inches) holes.
Known smart munitions, such as air-launched missiles and bombs, receive fire control instructions via an electrical cable with a quick-disconnect interconnection that disconnects when the smart munition is launched. The electrical cable (data link) supports electrical power transmission and bi-directional communications for the smart round. However, the design of both smart rounds and cannons do not support the quick-disconnect electrical cable type of interface. It may be possible to wirelessly communicate between the cannon and a smart round, but there are major disadvantages, such as external signal jamming, signal attenuation due to the large mass of the metal cannon surrounding the smart round, and the inability to support the power needs of the smart munition.
Traditional cannon firing circuits utilize complicated links and cams to actuate the firing pin that is in contact with the firing plug on the primer of a round. These firing circuits require extensive slots and cuts in the breechblock, which reduce the structural integrity and fatigue life of the breechblock and introduce numerous tightly toleranced linkage components. If a method similar to the traditional firing circuit were used for a cannon data link device, the resulting circuit would add many slots and cuts to the breechblock. As a result, the breechblock may not function as a part of the pressure vessel of the cannon. In addition, maintenance of the firing circuit, especially the firing pin, is a frequently performed procedure. In known firing circuits, there is no easy access to the firing pin cavity in the front of the breechblock.